Novel alpha-amino-substituted (3,4-methylenedioxy - phenyl) - alkanones and salts thereof



United States Patent 3,523,954 NOVEL or-ANHNO-SUBSTITUTED (3,4-METHYL- ENEDIOXY PHENYL) ALKANONES AND SALTS THEREOF Herbert Koppe, Ingelheim am Rheiu, Gerhard Ludwig, Wedel, Holstein, and Karl Zeile, Ingelheim am Rhein, Germany, assiguors to Boehringer Ingelheim G.m.b.H., Ingelheim am Rhein, Germany, a corporation of Germany No Drawing. Original application Mar. 30, 1965, Ser. No. 444,038. Divided and this application Mar. 7, 1968, Ser. No. 711,168

Int. Cl. C07d 19/00, 21/00 U.S. Cl. 260-3405 Claims ABSTRACT OF THE DISCLOSURE The compounds are 1-(3,4'-methylenedioxy-phenyl) -2- (lower alkyl-amino)-alkanones-(1) and acid addition salts thereof, useful as central nervous system stimulents in warm-blooded animals.

This is a division of copending application Ser. No. 444,038, filed Mar. 30, 1965, now abandoned.

This invention relates to a novel a-amino-substituted (3,4-methylenedioxy-phenyl)-alkanones and acid addition salts thereof, as well as to various methods of preparing these compounds.

More particularly, the present invention relates to racemic mixtures of compounds of the formula wherein R is straight-chain alkyl of 2 to 6 carbon atoms,

R is hydrogen or straightor branched-chain lower alkyl, and

R is straightor branched-chain lower alkyl,

an optically active antipode component thereof, or nontoxic, pharmacologically acceptable acid addition salts of said racemic mixture or of said optically active antipode. The free base compounds according to the present invention, that is, those embraced by Formula I above, may

be prepared by a variety of methods involving well known chemical principles, among which the following have been found to be most convenient and efiicient:

METHOD A (1) By reacting an whale-substituted (3,4-methylenedioxy-phenyl)-alkanone of the formula ice and at a temperature below C. It is preferred to provide a substantial excess of the amine III over and above the stoichiometric amount required for reaction with compound II in order to tie up or neutralize the hydrogen halide released by the reaction. However, an inorganic base or another organic base may be added to the-reaction mixture for the same purpose.

The reaction mixture may be worked up in customary fashion; for instance, by dissolving the reaction product in ether and precipitating it from solution as hydrohalide addition salt.

(2 An alternative variation of the method described in (1) above is the reaction of an a-halo-alkanone of the Formula II with the potassium salt of a phenylsulfonic acid alkylamide, preferably with the potassium salt of a toluenesulfonic acid alkylamide of the formula RMFSOQ wherein R has the same meanings as in Formula I, accompanied by release of potassium halide. The intermediate product is then transformed into a compound of the Formula I with the aid of an acid, especially by several hours boiling with concentrated hydrochloric acid accompanied by release of toluenesulfonic acid.

(3) A further alternative variation of the process described in (1) above comprises reacting a haloalkanone of the Formula II with an alkali metal alcoholate to form as an intermediate product an epoxyether of the formula oQ-o-oH-nn I o A wherein R has the same meanings as in Formula I and A is lower alkyl, and subsequently reacting the intermediate product with a primary or secondary amine of the Formula III. The reaction mixture is then worked up as described in (1).

METHOD B By alkylation a 1-(3,4-methylenedioxy-phenyl) 2- amino-alkanone-(l) of the formula 0 OQ-ii-CH-Rr L l l lHz H2 ---0 (VIII) 0 o-oH-R1 Hi) 0 2 R, 11 (VIb) wherein R and R have the same meanings as in Formula I, with an alkylating agent of the formula X or R Y 3 METHOD By converting the tertiary amino group of a 1-(3',4'- methylenedioxy-phenyl)-2-amino-alkanone-(1) of the for- N Ro \R3 (VIII) wherein R and R have the same meanings as in Formula I and R is a substituent which can be readily split off, into a secondary amino group (NI-IR Examples of substituents which may readily be split off include acyl and aralkyl substituents, especially carbobenzoxy and benzyl. In the event that R is aralkyl, such as benzyl, the conversion of R into hydrogen may, for example, be effected by selective hydrogenation with palladium chloride/animal charcoal in the presence of ethanol. If R is acyl, such as carbobenzoxy, its removal may be effected in conventional fashion, such as by hydrogenation or hydrolysis, provided the conditions are sufficiently mild.

METHOD D By oxidizing a (3,4-methylenedioxy-phenyl)-a-aminoalkanol of the formula OH N H2C-O R2 R3 (IX) wherein R R and R have the same meanings as in Formula I, with an oxidizing agent, such as chromic acid or an alkali metal dichromate. The oxidation reaction, which proceeds readily at room temperature or slightly elevated temperatures, may be performed in the presence of an aqueous solvent at an acid pH.

METHOD B By reacting a compound of the formula R7 R3 wherein Z is an unsubstituted or substituted carboxamide group or cyano and R and R have the same meanings as in Formula I, and R is lower alkyl, with a compound of the formula Q H: i

METHOD F By reacting an u-amino-cyanoalkane of the formula NECCIJHR1 R2 R3 (XII) wherein R R and R have the same meaning as in Formula I, with a benzene compound of the formula I H20 0 (XIII in the presence of a Friedel-Crafts catalyst, such as aluminum chloride, and subsequently hydrolyzing the ketimine reaction product.

The reaction between compounds XII and XIII may be carried out in the presence of a solvent customarily used for this type of reaction, such as nitrobenzene; when aluminum chloride is used as the catalyst, it proceeds smoothly at slightly elevated temperatures while introducing hydrogen chloride into the reaction mixture for several hours.

The compounds according to the present invention have opticaly active centers and therefore occur as racemic mixtures which may be divided into the respective optically active antipode components in customary fashion, such as by fractional crystallization of their diastereomeric salts with dibenzoyl-d-tartaric acid.

The compounds embraced by Formula I are organic bases and may, if desired, be converted into their nontoxic, pharmacologically acceptable acid addition salts by conventional methods, such as by dissolving the free base in a suitable solvent and acidifying the solution with the desired inorganic or organic acid. Examples of inorganic and organic acids which will form non-toxic, pharmacologically acceptable acid addition salts with the basic compounds of the Formula I above are hydrochloric acid, sulfuric acid, acetic acid, tartaric acid, maleic acid, sulfaminic acid, 8-chlorotheophylline and the like.

The following examples further illustrate the present invention and will enable others skilled in the art to understand it more completely. It should be understood, however, that the invention is not limited solely to the particular examples given below.

EXAMPLE 1 Preparation of 1 (3,4' methylenedioxy phenyl)-2- ethylamino-butanone-(l) and its hydrochloride by Method A 27.1 gm. (0.1 mol) of 1-(3,4'-methylenedioxyphenyl)- 2-bromo-butanone-(1) were dissolved in cc. of absolute benzene, and the resulting solution was cooled to 5 C. Thereafter, 18 gm. (0.4 mol) of ethylamine were added, and the mixture was allowed to stand at room temperature for 24 hours. Subsequently, the reaction mixture was heated for three hours on a boiling water bath, then allowed to cool, and the precipitated ethylamine hydrobromide was separated by filtration. The filtrate was evaporated, the residue was taken up in ether, the ethereal solution was Washed with water, and the ether phase was dried over magnesium sulfate. Thereafter, the ether was evaporated and the residue, 1-(3',4'- methylenedioxy-phenyl) 2 ethylamino-butanone-(l), was admixed with methanolic hydrochloric acid. Ether was added to the resulting solution, whereupon a precipitate formed which was collected and recrystallized from a mixture of methanol and ether. 17.2 gm. (63% of theory) of a compound having a melting point of 238- 239 C. were obtained, which was identified to be the hydrochloride of l (3,4' methylenedioxy-phenyl)-2- ethylamino-butanone-(l) of the formula Preparation of 1 (3',4' methylenedioxy phenyl)- 2-n-propylamino-pentanone-(1) and its hydrochloride by Method A 20.6 gm. (0.1 mol) of 1-(3,4'-methylenedioxy-phenyl)- pentanone-(l) were brominated with bromine in benzene, the developed hydrogen bromide was removed together with the benzene by evaporation. The raw 1-(3,4-methylenedioxy-phenyl) -2-bromo-pentanone- 1 obtained thereby was dissolved in 80 cc. of benzene, and the resulting solution was admixed with a solution of an excess of n-propylamine (0.6 mol) in 50 cc. of ether. The mixture Was taken up in ether, the ethereal solution was washed with water, and the organic phase was dried over sodium sulfate. The ether solution was evaporated and the residue, 1-(3',4 methylenedioxy-phenyl)-2-n-propylaminopentanone-(I), was acidified with methanolic hydrochloric acid. Ether was added to the resulting solution, whereupon a precipitate formed which was collected and recrystallized from a mixture of ethanol, methanol and ether. A compound having a melting point of 238-240 C. was obtained which was identified to be the hydrochloride of l-(3,4-methylenedioxy-phenyl)-2-n-propylamino-pentanone-(l) of the formula EXAMPLE 3 Using a procedure analogous to that described in Example 1, 1-(3',4-methylenedioxy-phenyl)-2-methylaminobutanone-(l) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-butanone-(1) and methylamine. Its hydrochloride had a melting point of 227-229" C.

EXAMPLE 4 Using a procedure analogous to that described in Example 1, 1 (3',4 methylenedioxy-phenyl)-2-n-propylaminobutanone-(l) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-butanone-(1) and n-propylamine. Its hydrochloride had a melting point of 232- 234 C.

EXAMPLE 5 Using a procedure analogous to that described in Example 1, 1-(3,4'-methylenedioxy-phenyl)-2-isopropylaminobutanone-(l) was prepared from l-(3,4'-methylenedioxy-phenyl) -2-bromo-butanone-( 1 and isopropylamine. Its hydrochloride had a melting point of 236- 238 C.

EXAMPLE 6 Using a procedure analogous to that described in Example 2, 1 (3',4' methylenedioxy-phenyl)-2-ethylamino-pentanone-(l) was prepared from 1-(3',4'-methyl,- enedioxy-phenyl) 2 bromo-pentanone (1) and ethylarnine. Its hydrochloride had a melting point of 238- EXAMPLE 7 Using a procedure analogous to that described in Example 2, 1-(3',4-methylenedioxy-phenyl)-2-isopropylamino-pentanone-(l) was prepared from 1-(3,4'-methylenedioxy-phenyl)-2-bromo-pentanone-l) and isopropylamine. Its hydrochloride had a melting point of 248- 251 C.

EXAMPLE 8 Using a procedure analogous to that described in Example 2, 1 (3",4 methylenedioxy-phenyl)-2-sec.- butylamino-pentanone-(l) was prepared from 1-(3',4'- methylenedioxy-phenyl) 2 bromo-pentanone-(l) and sec.butylamine. Its hydrochloride had a melting point of 226231 C.

EXAMPLE 9 Using a procedure analogous to that described in Example 2- 1-(3',4' methylenedioxy-phenyl)-2-methylamino-pentanone-(l) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-pentanone-(1) and methyl- 6 amine. Its hydrochloride had a melting point of 221- 225 C.

EXAMPLE 10 Using a procedure analogous to that described in Example 1, 1 (3',4' methylenedioxy-phenyl)-2-dimethylaminobutanone-(l) of the formula was prepared from 1-(3',4'-methylenedioxy-phenyl)-2- bromobutanone-(l) and dimethylamine. Its hydrochloride had a melting point of 219-221 C.

EXAMPLE 12 Using a procedure analogous to that described in Example 1, 1 (3',4 methylenedioxy-phenyl)-2-diethylamino-butanone-(l) was prepared from 1-(3',4'-methylenedioxy-phenyl) 2 bromo-butanone-(l) and diethylamine. Its hydrochloride had a melting point of 149- 152 C.

EXAMPLE 13 Using a procedure analogous to that described in Example 2, 1 (3,4' methylenedioxy-phenyl)-2-dimethylamino-pentanone-( 1) was prepared from 1-(3',4-methylenedioxy-phenyl)-2-bromo-pentanone 1) and dimethylamine. Its hydrochloride had a melting point of 225- 228 C.

EXAMPLE 14 Using a procedure analogous to that described in Example 2, 1 (3',4 methylenedioxy-phenyl)-2-diethylamino-pentanone-( 1) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-pentanone (1) and dimethylamine. Its hydro chloride had a melting point of 157- 159 C.

EXAMPLE 15 Using a procedure analogous to that described in Example 1, 1 (3',4' methylenedioxy-phenyl)-2-dimethylamino-hexanone-( 1) of the formula was prepared from 1-(3,4-methylenedioxy-phenyl)-2- bromo-hexanone-(l) and dimethylamine. Its hydrochloride had a melting point of 207.5-210" C.

EXAMPLE 16 Using a procedure analogous to that described in Example l, 1 (3',4' methylenedioxy-phenyl)-2-diethylamino-hexanone-(l) was prepared from l-(3,4'-methyl enedioxy-phenyl)-2-bromo-hexanone (1) and diethylamine. Its hydrochloride had a melting point of 133.5- 135 .5 C.

EXAMPLE 17 Preparation of 1- 3 ,4-methylenedioxy-phenyl) -2- ethyl-amino-pentanone-( 1) by Method B 1.256 gm. of 1-(3,4'-methylenedioxy-phenyl)-2-aminopentanone-(l) were dissolved in 30 cc. of aqueous 7 ethanol, the resulting solution was admixed With 0.78 gm. of ethyl iodide and 1.5 gm. of sodium bicarbonate, and the mixture was refluxed for two hours. Thereafter, the reaction mixture was evaporated in vacuo, the residue was taken up in water, the aqueous solution was made alkaline, and the solution was extracted with ether. The ether extract solution was evaporated, yielding about 60% of theory of 1-(3,4-methylenedioxy-phenyl)-2-ethylaminopentanone-( 1) EXAMPLE 18 Preparation of l-(3,4'-methylenedioxy-phenyl)-2- diethyl-amino-pentanone-( 1) by Method E 0.52 gm. of 1-(3',4'-methylenedioxy-phenyl)-2-diethylamino-pentanol-(l) were added to a chronic acid-pyridine complex compound prepared from 1.56 gm. C and gm. pyridine according to Sarett, J.A.C.S. 75, 427 (1953), and the resulting mixture was allowed to stand overnight at room temperature. Thereafter, the reaction mixture was stirred into water, the aqueous mixture was made alkaline, and the alkaline solution was extracted with ether. The ether extract solution was separated and the ether was distilled off. The oily residue contained about 40% of theory of 1-(3,4-methylenedioxy-phenyl)- 2-diethylamino-pentanone- 1 EXAMPLE 19 Using a procedure analogous to that described in Example 1, 1 (3',4' methylenedioxy-phenyl)-2-methylamino-hexanone (l) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-hexanone (1) and methylamine. Its hydrochloride had a melting point of 223.5- 225.5 C.

EXAMPLE 20 Using a procedure analogous to that described in Example 1, 1 (3',4' methylenedioxy-phenyl)-2-ethylamino-hexanone (1) was prepared from 1-(3,4-methylenedioxy-p'henyl)-2-bromo-hexanone (1) and ethylamine. Its hydrochloride had a melting point of 207.5210 C.

EXAMPLE 21 Using a procedure analogous to that described in Example 1, 1 (3',4' methylenedioxy-phenyl)-2-n-propylamino-hexanone 1) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-hexanone (1) and n-propylamine. Its hydrochloride had a melting point of 220 225 C.

EXAMPLE 22 Using a procedure analogous to that described in Example 1, l (3',4' methylenedioxy-phenyl)-2-isopropylamino-hexanone (1) was prepared from 1-(3',4'-methylenedioxy-phenyl)-2-bromo-hexanone (1) and isopropylamine. Its hydrochloride had a melting point of 222- 228 C.

EXAMPLE 23 Using a procedure analogous to that described in Example 1, l (3',4 methylenedioxy-phenyl-2-n-butylamino-hexanone 1) was prepared from 1-(3,4'-methylenedioxy-phenyl)-2-bromo-hexanone 1) and n-butylamine. Its hydrochloride had a melting point of 218- 222.5 C.

EXAMPLE 24 Using a procedure analogous to that described in Example 1, 1 (3',4-methylenedioxy-phenyl)-2-sec. butylamino-hexanone 1) was prepared from 1-(3',4-methylenedioxy-phenyl)-2-bromo-hexanone 1) and sec. butylamine. -Its hydrochloride had a melting point of 21l-220 C.

The compounds according to the present invention, that is, the racemates and optically active antipodes of those embraced by Formula I above as well as non-toxic acid addition salts of the racemates and optically active antipodes, have useful pharmacodynamic properties. More particularly, they exhibit very effective central nervous system stimulating activities in warm-blooded animals, such as mice.

1-(3',4-methylenedioxy-phenyl) 2 ethylamino-butanone-( 1) and its non-toxic additions salts, also exhibit anorexigenic properties in warm-blooded animals, such as rats.

The central nervous system stimulating activity and toxicity of the compounds according to the present invention were ascertained by means of the following standard pharmacological tests:

(1) Central nervous system stimulating activity Gradually increasing doses (5, 10, 15, 20, 25 and 30 mgm./kg.) of the compounds under investigation were administered subcutaneously in solution in distilled water to groups of five adult laboratory mice each, while the animals of a group of control animals received an equal volume of an aqueous 0.9% solution of sodium chloride by subcutaneous injection. Thereafter, the median effective dose (ED that is, the dose which produces nervous stimulation in 50% of the test animals, was determined by the method of Kar'ber, as described in Arch, Exp. Path. u. Pharma'kol, 162, 480 (1931).

(2) Toxicity The toxicity of the compounds under investigation was determined in the same manner as the central nervous system stimulating activity, except that higher doses (100, 200, 300 and 400 mgm./kg.) of the compounds were administered to the animals by subcutaneous injection, The median lethal dose (LD was determined by counting the number of animals which died within 24 hours after administration of each dose and calculating from the values thus obtained the dose which causes death in 50% of the animals, pursuant to K'zirber (loc. cit.).

Finally, the therapeutic index (TI), that is, the ratio LD /ED was calculated for each tested compound.

The following table shows the results obtained:

For pharmaceutical purposes the compounds according to the present invention are administered to warmblooded animals orally or parenterally as active ingredients in conventional dosage unit compositions, that is, compositions in dosage unit form consisting essentially of an inert pharmaceutical carrier and one dosage unit of the active ingredient, such as tablets, coated pills, sustained release tablets, capsules and the like. One oral dosage unit of the compounds according to the present invention is from 0.0166 to 2.5 mgrn./ kg. body weight, preferably 0.083 to 1.25 mgm./kg. One parenteral dosage unit is from 0.005 to 0.84 mgm./kg., preferably 0.0166 to 0.34 mgm./kg.

The following examples illustrate a few dosage unit compositions comprising a compound of the invention as an active ingredient and represent the best mode contem plated of putting the invention to practical use. The parts are parts by weight, unless otherwise specified.

9 EXAMPLE 25 Tablets The tablet composiiton was compounded from the fol- Compounding procedure.The butanone compound, the lactose and a substantial portion of the corn starch and of the silicic acid were thoroughly admixed with each other, and the mixture was moistened with an aqueous solution of the gelatin. The moist mass was forced through a 1.5 mm.-mesh screen, the moist granu late obtained thereby was dried for about twelve hours at 45 C. and the dry granulate was again passed through the screen. Thereafter, the granulate was thoroughly admixed with the remainder of the corn starch and of the silicic acid as well as with the magnesium stearate, and the resulting mixture was pressed into 450 mgm. tablets. Each tablet contained 35 mgm. of the butanone compound and, when administered perorally to a warm-blooded animal of about 60 kg. body weight in need of such treatment, produced very good CNS stimulating and anorexic effects.

EXAMPLE 26 Sustained-release tablets The tablet composition was compounded from the following ingredients:

Parts 1 (3',4' methylenedioxy-phenyl) 2 n-propyl Compounding procedure-The hydrogenated castor oil was heated to its melting point, the butanone compound was uniformly distributed therein, and the mixture was stirred until it had cooled to about room temperature. The solidified mass was then comminuted to a particle size of 1.5 mm., admixed with a filler granulate consisting of the lactose and the corn starch, and the mixture was uniformly admixed with the talcum and the magnesium stearate. The resulting composition was pressed into 50 mgm. tablets. Each tablet contained 3 mgm. of the pentanone compound and, when administered perorally to a warm-blooded animal of about 60 kg. body weight in need of such treatment, produced very good CNS stimulating elfects.

10 EXAMPLE 27 Hypodermic solution The solution was compounded from the following ingredients:

Parts 1- (3 (4'-methylenedioxy-pheny1) -2- ethylamino-butanone-(1) 15.0 Disodium salt of EDTA 1.0 Double distilled water q.s. ad 1000.0 by vol.

Compounding procedure.The butanone compound and the EDTA salt were dissolved in the distilled water, the solution was filtered until free from suspended particles, and the filtrate was filled into 2-ml. ampules which were then sterilized and sealed. Each ampule contained 30 mgm. of the butanone compound, and when the contents thereof were administered intravenously to a warmblooded animal of about 60 kg. body weight in need of such treatment, very good CNS stimulating and anorexic effects were obtained.

Although the above dosage unit composition examples illustrate the use of only three specific compounds of the present invention as active ingredients, it should be understood that any of the other compounds embraced by Formula I or an optical antipode thereof, or a non-toxic acid addition salt of either of these may be substituted for the particular compounds illustrated in Examples 19 through 21. Moreover, the amount of active ingredient in the above illustrative dosage unit compositions may be varied within the dosage unit limits set forth above, and the amounts and nature of the inert carrier components may be varied to meet particular requirements.

We claim:

1. A racemic mixture of a compound of the formula i H 11 b z R3 R2 wherein R is straight-chain alkyl of 2 to 4 carbon atoms, R is alkyl of 1 to 4 carbon atoms, and R is hydrogen or methyl,

an optically active antipode component thereof, or a nontoxic, pharmacologically acceptable acid addition salt of said racemic mixture or of said optically active antipode.

2. A compound according to claim 1, wherien R and R are ethyl, and R is hydrogen.

3. A compound according to claim 1, wherein R and R are n-propyl, and R is hydrogen.

4. A compound according to claim 1, wherein R is n-propyl, R is ethyl and R is hydrogen.

5. A compound according to claim 1, wherein R is nbutyl, R is ethyl and R is hydrogen.

OTHER REFERENCES Ohara, Journ. Pharm. Soc., Japan, vol. 71, 1951, pp. 1244-46.

ALEX MAZEL, Primary Examiner J. H. TURNIPSEED, Assistant Examiner US. Cl. X.R. 260-254; 424-282 

